/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */
package javax.swing;

import java.util.EventListener;

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;

import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;

import javax.swing.plaf.*;
import javax.accessibility.*;


/**
 * A menu item that can be selected or deselected. If selected, the menu
 * item typically appears with a checkmark next to it. If unselected or
 * deselected, the menu item appears without a checkmark. Like a regular
 * menu item, a check box menu item can have either text or a graphic
 * icon associated with it, or both.
 * <p>
 * Either <code>isSelected</code>/<code>setSelected</code> or
 * <code>getState</code>/<code>setState</code> can be used
 * to determine/specify the menu item's selection state. The
 * preferred methods are <code>isSelected</code> and
 * <code>setSelected</code>, which work for all menus and buttons.
 * The <code>getState</code> and <code>setState</code> methods exist for
 * compatibility with other component sets.
 * <p>
 * Menu items can be configured, and to some degree controlled, by
 * <code><a href="Action.html">Action</a></code>s.  Using an
 * <code>Action</code> with a menu item has many benefits beyond directly
 * configuring a menu item.  Refer to <a href="Action.html#buttonActions">
 * Swing Components Supporting <code>Action</code></a> for more
 * details, and you can find more information in <a
 * href="https://docs.oracle.com/javase/tutorial/uiswing/misc/action.html">How
 * to Use Actions</a>, a section in <em>The Java Tutorial</em>.
 * <p>
 * For further information and examples of using check box menu items,
 * see <a
 * href="https://docs.oracle.com/javase/tutorial/uiswing/components/menu.html">How to Use Menus</a>,
 * a section in <em>The Java Tutorial.</em>
 * <p>
 * <strong>Warning:</strong> Swing is not thread safe. For more
 * information see <a
 * href="package-summary.html#threading">Swing's Threading
 * Policy</a>.
 * <p>
 * <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with
 * future Swing releases. The current serialization support is
 * appropriate for short term storage or RMI between applications running
 * the same version of Swing.  As of 1.4, support for long term storage
 * of all JavaBeans&trade;
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @author Georges Saab
 * @author David Karlton
 * @beaninfo attribute: isContainer false description: A menu item which can be selected or
 * deselected.
 */
public class JCheckBoxMenuItem extends JMenuItem implements SwingConstants,
    Accessible {

  /**
   * @see #getUIClassID
   * @see #readObject
   */
  private static final String uiClassID = "CheckBoxMenuItemUI";

  /**
   * Creates an initially unselected check box menu item with no set text or icon.
   */
  public JCheckBoxMenuItem() {
    this(null, null, false);
  }

  /**
   * Creates an initially unselected check box menu item with an icon.
   *
   * @param icon the icon of the CheckBoxMenuItem.
   */
  public JCheckBoxMenuItem(Icon icon) {
    this(null, icon, false);
  }

  /**
   * Creates an initially unselected check box menu item with text.
   *
   * @param text the text of the CheckBoxMenuItem
   */
  public JCheckBoxMenuItem(String text) {
    this(text, null, false);
  }

  /**
   * Creates a menu item whose properties are taken from the
   * Action supplied.
   *
   * @since 1.3
   */
  public JCheckBoxMenuItem(Action a) {
    this();
    setAction(a);
  }

  /**
   * Creates an initially unselected check box menu item with the specified text and icon.
   *
   * @param text the text of the CheckBoxMenuItem
   * @param icon the icon of the CheckBoxMenuItem
   */
  public JCheckBoxMenuItem(String text, Icon icon) {
    this(text, icon, false);
  }

  /**
   * Creates a check box menu item with the specified text and selection state.
   *
   * @param text the text of the check box menu item.
   * @param b the selected state of the check box menu item
   */
  public JCheckBoxMenuItem(String text, boolean b) {
    this(text, null, b);
  }

  /**
   * Creates a check box menu item with the specified text, icon, and selection state.
   *
   * @param text the text of the check box menu item
   * @param icon the icon of the check box menu item
   * @param b the selected state of the check box menu item
   */
  public JCheckBoxMenuItem(String text, Icon icon, boolean b) {
    super(text, icon);
    setModel(new JToggleButton.ToggleButtonModel());
    setSelected(b);
    setFocusable(false);
  }

  /**
   * Returns the name of the L&amp;F class
   * that renders this component.
   *
   * @return "CheckBoxMenuItemUI"
   * @see JComponent#getUIClassID
   * @see UIDefaults#getUI
   */
  public String getUIClassID() {
    return uiClassID;
  }

  /**
   * Returns the selected-state of the item. This method
   * exists for AWT compatibility only.  New code should
   * use isSelected() instead.
   *
   * @return true  if the item is selected
   */
  public boolean getState() {
    return isSelected();
  }

  /**
   * Sets the selected-state of the item. This method
   * exists for AWT compatibility only.  New code should
   * use setSelected() instead.
   *
   * @param b a boolean value indicating the item's selected-state, where true=selected
   * @beaninfo description: The selection state of the check box menu item hidden: true
   */
  public synchronized void setState(boolean b) {
    setSelected(b);
  }


  /**
   * Returns an array (length 1) containing the check box menu item
   * label or null if the check box is not selected.
   *
   * @return an array containing one Object -- the text of the menu item -- if the item is selected;
   * otherwise null
   */
  public Object[] getSelectedObjects() {
    if (isSelected() == false) {
      return null;
    }
    Object[] selectedObjects = new Object[1];
    selectedObjects[0] = getText();
    return selectedObjects;
  }

  /**
   * See readObject() and writeObject() in JComponent for more
   * information about serialization in Swing.
   */
  private void writeObject(ObjectOutputStream s) throws IOException {
    s.defaultWriteObject();
    if (getUIClassID().equals(uiClassID)) {
      byte count = JComponent.getWriteObjCounter(this);
      JComponent.setWriteObjCounter(this, --count);
      if (count == 0 && ui != null) {
        ui.installUI(this);
      }
    }
  }


  /**
   * Returns a string representation of this JCheckBoxMenuItem. This method
   * is intended to be used only for debugging purposes, and the
   * content and format of the returned string may vary between
   * implementations. The returned string may be empty but may not
   * be <code>null</code>.
   *
   * @return a string representation of this JCheckBoxMenuItem.
   */
  protected String paramString() {
    return super.paramString();
  }

  /**
   * Overriden to return true, JCheckBoxMenuItem supports
   * the selected state.
   */
  boolean shouldUpdateSelectedStateFromAction() {
    return true;
  }

/////////////////
// Accessibility support
////////////////

  /**
   * Gets the AccessibleContext associated with this JCheckBoxMenuItem.
   * For JCheckBoxMenuItems, the AccessibleContext takes the form of an
   * AccessibleJCheckBoxMenuItem.
   * A new AccessibleJCheckBoxMenuItem instance is created if necessary.
   *
   * @return an AccessibleJCheckBoxMenuItem that serves as the AccessibleContext of this
   * AccessibleJCheckBoxMenuItem
   */
  public AccessibleContext getAccessibleContext() {
    if (accessibleContext == null) {
      accessibleContext = new AccessibleJCheckBoxMenuItem();
    }
    return accessibleContext;
  }

  /**
   * This class implements accessibility support for the
   * <code>JCheckBoxMenuItem</code> class.  It provides an implementation
   * of the Java Accessibility API appropriate to checkbox menu item
   * user-interface elements.
   * <p>
   * <strong>Warning:</strong>
   * Serialized objects of this class will not be compatible with
   * future Swing releases. The current serialization support is
   * appropriate for short term storage or RMI between applications running
   * the same version of Swing.  As of 1.4, support for long term storage
   * of all JavaBeans&trade;
   * has been added to the <code>java.beans</code> package.
   * Please see {@link java.beans.XMLEncoder}.
   */
  protected class AccessibleJCheckBoxMenuItem extends AccessibleJMenuItem {

    /**
     * Get the role of this object.
     *
     * @return an instance of AccessibleRole describing the role of the object
     */
    public AccessibleRole getAccessibleRole() {
      return AccessibleRole.CHECK_BOX;
    }
  } // inner class AccessibleJCheckBoxMenuItem
}
